US20240009889A1 - Plasticizing unit for a molding machine - Google Patents
Plasticizing unit for a molding machine Download PDFInfo
- Publication number
- US20240009889A1 US20240009889A1 US18/215,557 US202318215557A US2024009889A1 US 20240009889 A1 US20240009889 A1 US 20240009889A1 US 202318215557 A US202318215557 A US 202318215557A US 2024009889 A1 US2024009889 A1 US 2024009889A1
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- Prior art keywords
- plasticizing
- opening
- screw
- plasticized
- injection cylinder
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
- B29C45/47—Means for plasticising or homogenising the moulding material or forcing it into the mould using screws
- B29C45/50—Axially movable screw
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/20—Injection nozzles
- B29C45/24—Cleaning equipment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/40—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft
- B29B7/42—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix
- B29B7/422—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix with screw sections co-operating, e.g. intermeshing, with elements on the wall of the surrounding casing
- B29B7/423—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix with screw sections co-operating, e.g. intermeshing, with elements on the wall of the surrounding casing and oscillating axially
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/40—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft
- B29B7/42—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix
- B29B7/428—Parts or accessories, e.g. casings, feeding or discharging means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/58—Component parts, details or accessories; Auxiliary operations
- B29B7/72—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/80—Component parts, details or accessories; Auxiliary operations
- B29B7/801—Valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/1753—Cleaning or purging, e.g. of the injection unit
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
- B29C45/58—Details
Definitions
- the present invention relates to a plasticizing unit for a molding machine, a molding machine with such a plasticizing unit, a use of a plasticizing screw, a plasticizing method, as well as a control or regulating device for controlling or regulating a drive of a plasticizing screw of a plasticizing unit.
- Molding machines as used herein may include injection-molding machines, transfer-molding machines, presses and the like. Molding machines in which the plasticized material is supplied to an open mold are also entirely conceivable.
- Generic plasticizing units for injection-molding machines include an injection cylinder having a dispensing opening, via which dispensing opening a plasticized material can be dispensed, and a plasticizing screw arranged so as to be rotationally and linearly movable in the injection cylinder and has an axis of rotation.
- a plasticizing zone is formed between the plasticizing screw and the injection cylinder in the radial direction relative to the axis of rotation of the plasticizing screw.
- Corresponding plasticizing units are used in injection-molding machines to plasticize a plasticizable material through a rotational movement of the plasticizing screw.
- the plasticized material is plasticized due to the shear energy, shear heat, and optionally externally supplied heat energy. This generally takes place in the plasticizing zone of the plasticizing unit.
- the plasticized material is collected in a space that has formed—the space in front of the screw—wherein the plasticized material can be pushed out of the plasticizing unit through an axial movement of the plasticizing screw and injected into a mold cavity of a mold, where the plasticized material can in turn cure (and can thus solidify, for example, to form a finished product, molded part or semi-finished product).
- plastics can be for example recyclates, material to be ground or agglomerates, which are used for example in a recycling or compounding application.
- the contaminated material is plasticized by a continuously operating plasticizing unit and is then purified by degassing processes and filter systems.
- the plasticized material After filtration and degassing, the plasticized material is cooled again and solidifies, wherein the purified material is usually brought directly into a form that is easy to process further, such as for example granules.
- the granules produced from purified and degassed recycled material can then be used subsequently by an injection-molding process in an injection-molding machine.
- the object of the present invention is therefore to provide a plasticizing unit and/or a plasticizing method in which the disadvantages of the state of the art are at least in part improved and/or a more energy-efficient recycling of plasticizable material can be implemented and/or a more energy-efficient purification of material to be plasticized is possible and/or a direct processing of material to be purified and plasticized is made possible and/or a more continuous, rapid or energy-saving possibility for plasticizing plasticized material is presented.
- a plasticizing unit for a molding machine as described below a molding machine with such a plasticizing unit, a use of a plasticizing screw as described below, a plasticizing method as described below, and/or a control or regulating device for controlling or regulating a drive of a plasticizing screw as described below.
- a plasticizing unit for a molding machine includes an injection cylinder having a dispensing opening, via which dispensing opening a plasticized material can be dispensed, and a plasticizing screw arranged so as to be rotationally and linearly movable in the injection cylinder and has an axis of rotation.
- a plasticizing zone is formed between the plasticizing screw and the injection cylinder in the radial direction relative to the axis of rotation of the plasticizing screw.
- the plasticizing screw has a dam element
- the injection cylinder has a first opening in the area of the plasticizing zone and/or the dam element, and a has second opening between the dam element and the dispensing opening.
- the present invention thus makes it possible to also use contaminated materials in a process in a molding machine, in particular an injection-molding machine, wherein the contaminated material is plasticized via the plasticizing unit of the molding machine, is guided out of the injection cylinder, can be purified and is then supplied to the injection cylinder again, in order to push out the purified, plasticized material via the plasticizing screw and supply it for example to a mold, more precisely: a mold cavity of a mold.
- a simple possibility is created for placing a filter device for the plasticized material outside the injection cylinder, wherein through a molten material line the redirection of the plasticized material, the filter device is virtually freely dimensionable and positionable on the molding machine or the plasticizing unit.
- the filter device can thereby be precisely adapted to the requirements of the filtering process irrespective of the size of the injection cylinder.
- a cleaning of the filter device or an exchange of filter elements possibly present can be simplified to the effect that the accessibility of the filter device is increased.
- a further advantage is created to the effect that plasticizing units known from the state of the art with plasticizing screws which serve on the one hand for plasticizing and on the other hand for injecting the plasticized material can be utilized, whereby a very compact design of the plasticizing unit can be implemented even in the case of processing of contaminated materials.
- a corresponding application of an embodiment of the present invention can thus also make a recycling application or compounding application considerably more attractive to a user, wherein the production costs and the production effort are minimized, whereby the environmental friendliness can be increased (through increased use).
- a plasticizing unit according to the invention can have precisely one plasticizing screw or also be formed as a twin-screw design or multi-screw design.
- the plasticizing screw singular
- the plasticizing screw is sometimes mentioned. However, this is to be understood such that analogous embodiments with several plasticizing screws are likewise applicable.
- molding machines may be meant injection-molding machines, transfer-molding machines, presses and the like. Molding machines in which the plasticized material is supplied to an open mold are also entirely conceivable.
- a filtration and/or a filtering of a plasticized material may be meant that foreign substances present in the plasticized material are, preferably mechanically, released, removed, discharged and/or separated at least partially from the plasticized material. This can thus also include a separation method.
- the dispensing opening of the injection cylinder is connected to at least one injection nozzle and/or a shutoff nozzle and/or is formed as such.
- the at least one injection nozzle and/or shutoff nozzle can be attached to a mold, in particular an injection mold, and a plasticized material can be supplied to the mold and/or injected into the mold from the injection cylinder via the at least one injection nozzle and/or shutoff nozzle.
- At least one molten material line can be provided, which fluidically connects the first opening to the second opening.
- the at least one molten material line is preferably formed to at least partially supply a plasticized material emerging from the first opening of the injection cylinder to the injection cylinder again via the second opening.
- At least one filter device for filtering plasticized material is or can be arranged in the at least one molten material line.
- the at least one molten material line has at least one valve element, preferably a check valve.
- the at least one valve element is arranged in the at least one molten material line between the at least one filter device and the connection of the second opening of the injection cylinder.
- plasticized material preferably filtered plasticized material
- flow direction for example during the injection process
- the valve element can be formed as a controllable or regulatable valve element or as a nonreturn valve.
- the valve element can be a two- or three-way valve.
- At least one sensor can be provided in the molten material line, for example in order to detect a signal characteristic of a state and/or a contamination of the plasticized material and/or the filter device.
- a corresponding sensor can be formed as a pressure sensor, temperature sensor, ultrasonic sensor, color sensor, rheometer and/or spectrometer.
- a control or regulating device can take into account a characteristic signal of the at least one sensor in the molten material line for the control or regulation.
- the at least one molten material line has at least one discharge opening, preferably between the at least one filter device and the first opening of the injection cylinder.
- plasticized material can be discharged from the molten material line, in order to be able to flush the plasticized material out of the molten material line for example before shutdown of the process, in order to be able to prevent solidification in the molten material line.
- a further aspect which is made possible through the provision of a discharge opening is the cleaning of the filter device.
- an outlet opening of the injection cylinder is closed and plasticized material is collected in the space in front of the screw.
- a space in front of the screw can be formed along the axis of rotation of the plasticizing screw between an end of the plasticizing screw facing the dispensing opening and the dispensing opening.
- a pressure is then exerted on this plasticized material collected in the space in front of the screw (the melt cushion) via the plasticizing screw, the dam element and/or the injection plunger.
- the plasticized material flows back into the molten material line via the second opening—as the outlet opening is closed—and thus runs through the filter device in the opposite direction, whereby deposits and contaminants are removed from the filter device (i.e. the filter device is backflushed).
- a discharge opening can now be provided between filter device and first opening of the injection cylinder and opened, with the result that the backflushed plasticized material with the contaminants carried therein can be discharged from the filter device.
- Such a corresponding backflushing process can for example be carried out between the production cycles of the plasticizing unit after a given number of cycles or for example in the presence of measurement data which indicate an increased filter blocking.
- a filter blocking or filter coating can, for example, be determined by the measurement of a pressure before the filter device and after the filter device, wherein the pressure difference prevailing between the two measurements represents a meaningful measure thereof.
- the at least one filter device has a filter change device, preferably wherein the filter device is formed as a cassette filter.
- a cassette filter can have two or more filter elements, wherein a first filter element in an engaged position is located in a melt stream of the plasticized material, in order to perform a filtration of the plasticized material. In the meantime, a further filter element of the cassette filter is released and is not in contact with the plasticized material.
- the further filter element of the cassette filter can be cleaned of contaminants or exchanged.
- the further filter element can be brought into an engaged position via a change device, wherein a filtration of the plasticized material by the further filter element takes place and the first filter element is released for cleaning or changing.
- the filter device can be formed similarly to a cassette deck and have two or more receiving devices for filter elements, wherein, through a change device (preferably an actuator), a receiving device can selectively be brought into an engaged position with the plasticized material and/or a released filter element can be positioned out of or in the receiving device.
- a change device preferably an actuator
- the filter change device can, for example, be formed as a plate screen changer, piston screen changer, cassette screen changer and/or belt filter.
- a belt filter is provided as filter change device, the belt filter can be guided through the melt stream of the plasticized material continuously or at intervals, wherein blocked filter regions or contaminants of the at least one filter device can be moved out of the melt stream of the material to be plasticized by the filter change device, in order not to impair the ongoing process of the plasticizing unit.
- the moving in and/or out of the at least one filter device can for example take place in an operating state of the plasticizing unit, in which a melt stream of plasticized material is not actively being pushed out by the plasticizing screw, with the result that an active pressure due to a melt stream of the plasticized material does not act on the at least one filter device during the moving in and/or moving out by the filter change device.
- At least one actuator can be provided for conveying the plasticized material against the flow direction of the melt stream, in order to relieve a pressure of the plasticized material applied to the at least one filter device.
- the possibility can be created to influence, utilizing the at least one actuator, pressure conditions prevailing on the at least one filter device (which act on the at least one filter device through the plasticized material) such that a pressure relief of the at least one filter device—which can for example be utilized for a filter change—can be carried out.
- This is preferably possible without additionally sealing the at least one filter device off from the melt stream of the plasticized material (for example using a check valve).
- a pressure relief may be meant relieving substantial pressures on the at least one filter device.
- a pressure relief may also be meant a relief of the at least one filter device when an approximately equal pressure is exerted on the at least one filter device from both sides.
- the at least one actuator is formed by the plasticizing screw and/or by a plunger-cylinder unit, preferably in the form of a melt accumulator.
- the plunger-cylinder unit can be arranged between the at least one filter device and the plasticizing screw in terms of flow or is arranged after the at least one filter device in terms of flow.
- a pressure relief and/or backflushing of the at least one filter device can thus be performed through an axial movement of the plasticizing screw against the flow direction of the plasticized material.
- the dam element can separate the first opening and the second opening from each other in a pushed-forward position, a pulled-back position and/or every operating position lying in between.
- a pushed-forward position of the dam element minus a pulled-back position of the dam element can correspond to a metering stroke of the plasticizing screw.
- the plasticizing screw has an injection plunger at the end facing the dispensing opening and/or is coupled to an injection plunger in a movement-locking manner linearly along the axis of rotation.
- the injection plunger can be connected to the plasticizing screw and is formed to execute a relative movement with respect to the plasticizing screw, preferably along an axis of rotation of the plasticizing screw.
- the dam element can be arranged concentrically in the injection cylinder.
- the dam element can be designed as a component that is separate from the plasticizing screw, and can be connected to the plasticizing screw, for example, via a connection, preferably a screw connection. However, it is also entirely conceivable that a part of the plasticizing screw itself is formed as a dam element.
- the dam element can be rotationally decoupled from the injection screw, with the result that a rotational movement of the plasticizing screw (such as occurs, for example, during the plasticizing) is not necessarily transferred to the dam element.
- dam element can also be connected to the plasticizing screw in a movement-locking manner (and thus also rigidly with respect to a rotational movement).
- An injection plunger and/or the dam element can be formed so that it has an outer contour which corresponds to the inner contour of the injection cylinder, wherein between the injection cylinder on the one hand and the injection plunger and/or dam element on the other hand a cross section transverse to an injection direction is formed which is only interrupted by a gap between the injection plunger and/or dam element on the one hand and the injection cylinder on the other hand.
- This gap is preferably to be designed so small that a plasticized material cannot penetrate through the gap (apart from negligible leakage which does not affect the process or only insignificantly affects it).
- the plasticizing zone can be separated from the space in front of the screw, whereby the plasticized material is necessarily channeled through the first opening and preferably a molten material line and thus has to pass through a filtration in the molten material line, for example.
- the injection plunger and/or the dam element with a circumferential surface that is the opposite of the injection cylinder, can be formed leakproof with respect to a plasticized material.
- leakproof is to be interpreted such that a leakproofness sufficient for the process cycle can be implemented and operational leakage (for example formed due to wear and tear, tolerances or also damage between injection cylinder and plasticizing screw, dam element or injection plunger) may still be present.
- the first opening from the plasticizing zone and the second opening can be at a distance from each other which corresponds to at least an injection stroke of the plasticizing screw during an injection movement, preferably an injection stroke of the plasticizing screw plus a longitudinal dimension of the dam element along the injection movement.
- the plasticizing screw can have a conveying geometry.
- This conveying geometry can be formed to convey the material to be plasticized and the plasticized material in the direction of the dispensing opening with a given rotational direction and to plasticize it via a shearing and shear heat that forms.
- At least one further conveying geometry can be provided between the dam element and first opening, preferably which further conveying geometry is connected to the plasticizing screw in a movement-locking manner.
- the filtered plasticized material which enters the injection cylinder again from the molten material line is plasticized (heated) a further time by shearing and shear heat between the dam element and the dispensing opening and is thus conveyed in the space in front of the screw in the direction of the dispensing opening.
- the “first-in/first-out” principle can also furthermore be implemented, wherein the filtered plasticized material which is supplied from the molten material line to the injection cylinder in the space in front of the screw can be coordinated to the effect that the plasticized material supplied earlier is also the first to leave the injection cylinder again.
- the first opening and/or the second opening can be formed by at least one recess in the injection cylinder.
- the at least one recess in the injection cylinder can be formed as a longitudinal groove along the axis of rotation, which longitudinal groove preferably has a varying width along the axis of rotation.
- the feeding of the molten material line and thus of the filter device can be controlled or regulated.
- Protection is also sought for the use of a plasticizing screw with a dam element for retaining the plasticized material, in conjunction with a plasticizing unit, preferably a plasticizing unit according to the invention, with an axially movable mounting of the plasticizing screw and preferably an axial drive for the plasticizing screw.
- the plasticizing screw can have a conveying geometry for plasticizing and conveying a material to be plasticized, preferably a plastic.
- the plasticized material can be conveyed out of the injection cylinder into at least one molten material line and is particularly preferably filtered by at least one filter device in the at least one molten material line.
- a space in front of the screw can be formed along the axis of rotation of the plasticizing screw between an end of the plasticizing screw facing the dispensing opening and the dispensing opening.
- the filtered plasticized material is pushed out of a space in front of the screw present between the plasticizing screw and a dispensing opening of the injection cylinder via the dispensing opening of the injection cylinder by a dam element coupled to the plasticizing screw in a movement-locking manner or attached to the plasticizing screw via a linear movement of the plasticizing screw.
- a pressure can be exerted on the filtered plasticized material by a linear movement of the injection screw, whereby the filtered plasticized material is conveyed back into at least one molten material line arranged at the second opening, preferably whereby at least one filter device arranged in the at least one molten material line is backflushed.
- Protection is furthermore sought for a control or regulating device for controlling or regulating a drive of a plasticizing screw of an embodiment according to the invention of a plasticizing unit, which control or regulating device is formed to carry out a method according to the invention.
- the control or regulating device can be formed for controlling or regulating a filter device, a filter change device, a valve element, a discharge opening, a plasticizing screw. It can alternatively or additionally be provided that the control or regulating device is formed to control or regulate a drive device, a drive and/or a control or regulating element of one of the previously listed elements.
- the control or regulating device is or can be connected in a signal-carrying manner to at least one sensor, wherein preferably a characteristic signal of the at least one sensor is taken into account for the control or regulation.
- a control or regulating device may be meant those components of a plasticizing unit which allow a control of actuators, drives and/or drive control systems, which in particular comprises so-called “programmable logic controllers” (PLCs).
- PLCs programmable logic controllers
- This can also include receiving sensor data and carrying out calculation processes for a control process, which can be carried out in real time depending on the control diagram.
- the control or regulating unit can be realized by a central machine control system or a control or regulating unit of the molding machine or undertakes the tasks thereof.
- control or regulating device can be undertaken by a control or regulating device linked directly to the molding machine and/or the plasticizing unit or a control or regulating device connected to the molding machine and/or the plasticizing unit by a data transmission connection.
- the data transmission connection can preferably be formed as a remote data transmission connection.
- the remote data transmission connection can be realized by means of a LAN (Local Area Network), WLAN (Wireless Local Area Network), WAN (Wide Area Network) and/or different (internet) protocols.
- the data transmission and relaying to the manufacturer or a maintenance service provider, as well as the processing by them, can likewise be provided.
- the at least one control or regulating device can be formed to control or regulate the plasticizing screw and/or a drive of the plasticizing screw taking into account characteristic signals of at least one sensor, preferably at least one sensor in the molten material line, so that a filter device in the molten material line between the first opening and the second opening is backflushed.
- Such a sensor can be, for example, at least one or a combination of the following:
- control or regulating device can be formed to perform and/or signal a necessary filter change and/or a filter cleaning of the filter device because of the determined filter blocking or filter coating.
- a corresponding filter change and/or a filter cleaning can for example be signaled, by the control or regulating device through acoustic, haptic and/or optical signals, to a user who can initiate a filter change and/or a filter cleaning. It can also be provided that, in the case of too great a filter blocking or filter coating, the control or regulating device is formed to automatically interrupt the plasticizing process, in order to carry out a filter change and/or a filter cleaning.
- a signal characteristic of the determined filter blocking or the filter coating can be transmitted by the control or regulating device to a manufacturer or a maintenance service provider, who, on the basis of the transmitted signals, can provide, for example in an automated manner, maintenance personnel and/or maintenance material (such as for example filter elements for the filter device) for the filter change and/or for the filter cleaning.
- a manufacturer or a maintenance service provider who, on the basis of the transmitted signals, can provide, for example in an automated manner, maintenance personnel and/or maintenance material (such as for example filter elements for the filter device) for the filter change and/or for the filter cleaning.
- control or regulating device When a filter change is carried out, the control or regulating device can be formed:
- control or regulating device When a filter cleaning is carried out, the control or regulating device can be formed:
- FIGS. 1 and 2 show a first embodiment of a plasticizing unit according to the invention
- FIGS. 3 and 4 show a second embodiment of a plasticizing unit according to the invention
- FIG. 5 shows a third embodiment of a plasticizing unit according to the invention
- FIG. 6 shows a fourth embodiment of a plasticizing unit according to the invention
- FIG. 7 shows a fifth embodiment of a plasticizing unit according to the invention
- FIG. 8 shows a sixth embodiment of a plasticizing unit according to the invention
- FIGS. 9 and 10 show a seventh embodiment of a plasticizing unit according to the invention.
- FIGS. 11 and 12 show an eighth embodiment of a plasticizing unit according to the invention
- FIGS. 13 and 14 show a ninth embodiment of a plasticizing unit according to the invention
- FIG. 15 shows a tenth embodiment of a plasticizing unit according to the invention
- FIGS. 16 a - 16 c show a filter device with filter change device
- FIG. 17 shows a molding machine
- FIG. 1 shows a first embodiment of a plasticizing unit 1 , comprising an injection cylinder 4 and a plasticizing screw 5 arranged in the injection cylinder 4 .
- the plasticizing screw 5 is formed to perform, in the injection cylinder 4 , a rotational movement about the axis of rotation 6 for plasticizing a material, as well as to perform a linear movement along the axis of rotation 6 for pushing out the plasticized material.
- the injection cylinder 4 has a dispensing opening 3 , via which dispensing opening 3 plasticized material can be pushed out of the injection cylinder and can for example be injected into a mold 24 .
- a space in front of the screw 7 is provided along the axis of rotation 6 of the plasticizing screw 5 between the dispensing opening 3 and the end of the plasticizing screw 5 facing the dispensing opening 3 .
- the plasticizing zone 8 is formed between the plasticizing screw 5 and the injection cylinder 4 in the radial direction relative to the axis of rotation 6 of the plasticizing screw 5 .
- a molten material line 9 is furthermore provided, which branches off from the injection cylinder 4 out of the plasticizing zone 8 via the first opening 12 of the injection cylinder 4 and opens into the injection cylinder 4 again via the second opening 13 of the injection cylinder 4 with the space in front of the screw 7 .
- the plasticizing screw furthermore has a dam element 11 at an end facing the dispensing opening 3 , wherein in this embodiment the dam element 11 is formed in one piece with the plasticizing screw 5 .
- the filter device 10 for filtering a plasticized material is furthermore provided in the bypass line 9 .
- the molten material line 9 can be sealed off with respect to the space in front of the screw 7 by means of the valve element 16 —to be precise: a check valve.
- a material to be plasticized is now moved from a rear area of the plasticizing screw 5 via the conveying geometry 15 of the plasticizing screw 5 in the direction of the plasticizing zone 8 , wherein due to the shearing, shear heat and optionally externally introduced heat the material to be plasticized is plasticized in the plasticizing zone 8 .
- the material and the plasticized material are conveyed by the conveying geometry 15 of the plasticizing screw 5 in the direction of the dispensing opening 3 until the plasticized material emerges from the plasticizing zone 8 via the first opening 12 from the injection cylinder 4 and is channeled into the molten material line 9 .
- the dam element 11 has an external geometry that corresponds to the internal geometry of the injection cylinder 4 , with the result that between dam element 11 and injection cylinder 4 only a small gap remains, which is chosen so that it is formed leakproof with respect to a plasticized material.
- the material plasticized by the plasticizing screw 5 is thus driven through the molten material line 9 and the filter device 10 arranged therein.
- the filter device 10 is formed to filter contaminants out of the plasticized material, wherein these contaminants remain in the filter device and the filtered plasticized material is channeled through the molten material line 9 via the valve element 16 and the second opening 13 of the injection cylinder 4 back into the injection cylinder 4 —to be precise: into the space in front of the screw 7 .
- the filtered plasticized material now accumulates in the space in front of the screw 7 .
- a melt cushion consisting of plasticized material builds up in the space in front of the screw 7 , which pushes the plasticizing screw 5 away backwards, whereby the space in front of the screw 7 increases in size.
- This plasticizing process (often also referred to as metering) is performed until a desired quantity of plasticized material is present in the space in front of the screw 7 (as can be seen in FIG. 2 ).
- the valve element 16 is closed, the dispensing opening 3 is opened and then the dam element 11 is moved in the direction of the dispensing opening 3 via a linear movement of the plasticizing screw 5 , wherein, via the dam element 11 , the plasticized material is pushed out of the space in front of the screw 7 via the dispensing opening 3 and is for example supplied to a mold 24 —to be precise: a cavity of the mold 24 .
- FIGS. 3 and 4 show a further embodiment of a plasticizing unit 1 , wherein the plasticizing unit is again represented during a plasticizing in FIG. 3 , and FIG. 4 shows the plasticizing unit 1 just before the injection process.
- the embodiment of the plasticizing unit 1 of FIGS. 3 and 4 has a plasticizing screw 5 which is again formed in one piece with a dam element 11 , but wherein between dam element 11 and dispensing opening 3 a further conveying geometry 14 is provided, which is formed by a screw extension.
- the plasticized material returned to the space in front of the screw 7 via the second opening 13 can be conveyed, via this further conveying geometry 14 , further in the direction of the dispensing opening 3 and heated/plasticized once again via shearing and shear heat.
- a nonreturn valve 30 which serves to prevent the plasticized material from flowing back out of the space in front of the screw 7 to the further screw geometry 14 during the injection, is arranged at the end of the further conveying geometry 14 facing the dispensing opening 3 .
- a valve element 16 is not necessary in the embodiment of FIGS. 3 and 4 .
- the plasticizing screw 5 as represented in FIGS. 4 and 5 , only has a cylindrical extension instead of the further screw geometry 14 , wherein a nonreturn valve 30 can be arranged at an end of the cylindrical extension facing the dispensing opening, wherein a valve element 16 can likewise be dispensed with by means of such an embodiment.
- FIG. 5 shows a third embodiment of a plasticizing unit 1 which, in comparison with the embodiment of FIG. 1 , has a converse conveying geometry 35 on the plasticizing screw 5 .
- This converse conveying geometry 35 is formed in an area between the first opening 12 and the second opening 13 of the injection cylinder 4 , more precisely in an area between the first opening 13 and the dam element 11 .
- the converse conveying geometry 35 of the plasticizing screw 5 changes from the conveying geometry 15 of the plasticizing screw 5 into the converse conveying geometry 35 .
- the plasticized material can additionally be retained in the area of the transition from the conveying geometry 15 into the converse conveying geometry 35 and an emerging of the plasticized material from the injection cylinder 4 through the first opening 12 can be promoted.
- FIG. 6 shows a fourth embodiment of a plasticizing unit 1 which, in comparison with the embodiment of FIG. 1 , has a dummy 36 instead of the filter device 10 .
- Such a dummy 36 or also placeholder can for example be inserted into the molten material line 9 for delivery and/or transport of the plasticizing unit 1 , in order to prevent damage.
- this dummy 36 can be removed from the molten material line 9 and replaced with a filter device 10 for the filtration of the plasticized material.
- the dummy 36 and/or the filter device 10 are replaced with a connecting pipe or a continuous molten material line 9 , wherein a clean material to be plasticized, which requires no further filtration (as can be seen in the fifth embodiment of FIG. 7 ), can for example be processed.
- FIG. 8 shows a sixth embodiment of a plasticizing unit 1 , which has a control or regulating device 37 .
- This control or regulating device 37 of the plasticizing unit 1 is connected by signal-carrying connections (represented dashed here) to a drive unit 26 of the plasticizing screw 5 , a filter change device 17 of the filter device 10 , the valve element 16 and a shutoff nozzle 38 of the dispensing opening 3 , wherein the control or regulating device 37 , with the aid of the signal-carrying connections, is formed to control or regulate these elements and optionally receive characteristic signals from sensors which are arranged on these elements.
- control or regulating unit 37 can be formed, for example for the measurement of a coating or blocking of the filter device 10 , to measure a pressure before and after the filter device 10 with the aid of correspondingly arranged pressure sensors and via the pressure difference between these two pressures—when the pressure difference becomes too great—to indirectly refer to the coating or blocking of the filter device 10 .
- control or regulating unit 37 can be formed to carry out a filter change and/or a filter cleaning.
- a filter change can be performed by the control or regulating unit 37 through a corresponding control or regulation of actuators of the plasticizing screw 5 and the filter change device 17 . Reference may be made at this point to the following FIGS. 16 a to 16 c , wherein a filter change will be expanded on.
- a backflushing can for example be performed, wherein a cleaning of the filter device by backflushing the plasticized material through the filter device 10 can be performed by the control or regulating device 37 (as already described previously) through a corresponding control or regulation of the plasticizing screw 5 , the valve element 16 , a shutoff nozzle 38 of the dispensing opening 3 and optionally an actuator or valve element 16 of a discharge opening.
- FIGS. 9 and 10 show a further embodiment of a plasticizing unit 1 , wherein the plasticizing screw 5 has an injection plunger 39 .
- a material to be plasticized is now moved from a rear area of the plasticizing screw 5 via the conveying geometry 15 of the plasticizing screw 5 in the direction of the plasticizing zone 8 , wherein due to the shearing, shear heat and optionally externally introduced heat the material to be plasticized is plasticized in the plasticizing zone 8 .
- the material and the plasticized material are conveyed by the conveying geometry 15 of the plasticizing screw 5 in the direction of the dispensing opening 3 until the plasticized material emerges from the plasticizing zone 8 via the first opening 12 from the injection cylinder 4 and is channeled into the molten material line 9 .
- the material plasticized by the plasticizing screw 5 is thus driven through the molten material line 9 and the filter device 10 arranged therein.
- the filter device 10 is formed to filter contaminants out of the plasticized material, wherein these contaminants remain in the filter device and the filtered plasticized material is channeled through the molten material line 9 via the valve element 16 and the second opening 13 of the injection cylinder 4 back into the injection cylinder 4 —to be precise: into the space in front of the screw 7 .
- the filtered plasticized material now accumulates in the space in front of the screw 7 .
- a melt cushion consisting of plasticized material builds up in the space in front of the screw 7 , which pushes the injection plunger 39 away backwards, whereby the space in front of the screw 7 increases in size.
- This plasticizing process (often also referred to as metering) is performed until a desired quantity of plasticized material is present in the space in front of the screw 7 (as can be seen in FIG. 9 ).
- valve element 16 is closed, the dispensing opening 3 is opened and then dam element 11 is moved in the direction of the dispensing opening 3 via a linear movement of the injection plunger 39 of the plasticizing screw 5 , wherein, via the injection plunger 39 , the plasticized material is pushed out of the space in front of the screw 7 via the dispensing opening 3 and is for example supplied to a mold 24 —to be precise: a cavity of the mold 24 (as can be seen in FIG. 10 ).
- FIGS. 9 and 10 substantially correspond to those of FIGS. 1 and 2 .
- FIG. 11 and FIG. 12 show an embodiment which, in comparison with the embodiment of FIG. 5 and FIG. 6 , has a nonreturn valve instead of a valve element 16 formed as a 2-way valve.
- FIG. 13 and FIG. 14 show an embodiment which, in comparison with the embodiment of FIG. 3 and FIG. 4 , has a converse conveying geometry 35 on the plasticizing screw 5 .
- This converse conveying geometry 35 is formed in an area between the first opening 12 and the second opening 13 of the injection cylinder 4 , more precisely in an area between the first opening 13 and the dam element 11 .
- the converse conveying geometry 35 of the plasticizing screw 5 changes from the conveying geometry 15 of the plasticizing screw 5 into the converse conveying geometry 35 .
- the plasticized material can additionally be retained in the area of the transition from the conveying geometry 15 into the converse conveying geometry 35 and an emerging of the plasticized material from the injection cylinder 4 through the first opening 12 can be promoted.
- the first opening 12 is formed as a recess in the injection cylinder 4 , which recess is formed by a longitudinal groove with a varying width along the axis of rotation 6 , as can be seen in the embodiment of FIG. 15 .
- FIG. 15 shows a top view of an injection cylinder 4 , wherein the inside of the injection cylinder 4 and thus the plasticizing screw 5 arranged in the injection cylinder 4 can be recognized through the first opening 12 .
- a flow direction of the plasticized material is illustrated by the arrow represented, wherein the material plasticized by the plasticizing screw 5 is conveyed in the direction of the first opening 12 , before the plasticized material leaves the injection cylinder 4 via the first opening 12 .
- dam element such as for example in the case of an embodiment of FIGS. 1 - 8 or 13 - 14
- plasticizing screw 5 now makes an axial movement in the injection cylinder 4 , it may be the case that, in certain operating states, areas of the first opening 12 are at least partially covered (see in particular FIG. 2 ).
- the feeding of the molten material line 9 and thus of the filter device 10 can be controlled or regulated, depending on what proportion of the first opening 12 is cleared by the dam element 11 .
- the dam element Due to the varying width of the first opening 12 , it can be achieved that for example a relatively large melt stream gets through the first opening 12 , even if a relatively small part of the first opening 12 is cleared by the dam element.
- the melt stream can be relatively finely regulated in the area of the maximum melt stream (if the first opening 12 is completely or almost completely cleared) in that the first opening 12 at the end that is on the left in FIG. 15 is relatively narrow.
- FIGS. 16 a to 16 c show, purely schematically, a filter device 10 which has a filter change device 17 .
- This filter change device 17 has a first filter element 33 and a (further) second filter element 34 , which can be alternately added to a fluid stream 31 consisting of plasticized material in order to filter the plasticized material and/or to remove contaminants from it.
- first of all a first filter element 33 is located in the molten material line 9 in order to filter the fluid stream 31 of plasticized material.
- a pressure can for example be measured before and after the filter element 33 , 34 and via the pressure difference between these two pressures—when the pressure difference becomes too great—the coating of the filter element 33 , 34 can be referred to indirectly.
- the cyclic filter change represents an alternative solution, wherein, according to empirical values, the filter elements 33 , 34 are exchanged after a certain number of plasticizing cycles have been carried out.
- the fluid stream 31 of plasticized material is briefly interrupted and, via a change system 32 , the first filter element 33 is taken out of the molten material line 9 and replaced with the second filter element 34 .
- the fluid stream 31 of plasticized material can be started again and supplied to the second filter element 34 (see FIG. 16 c ).
- the filter element 33 can then be cleaned while the second filter element 34 is being used and exchanged again once a coating of the second filter element 34 in the fluid stream 31 of plasticized material becomes too great.
- the molten material line 9 is formed as a hotrunner system, with the result that during the filter change the plasticized material in the molten material line 9 does not cool too much and possibly solidify.
- the molding machine 2 represented by way of example in FIG. 17 is an injection-molding machine and has an injection unit 18 and a clamping unit 19 , which are arranged together on a machine frame 20 .
- the machine frame 20 could alternatively also be formed multi-part.
- the clamping unit 19 has a fixed platen 21 , a movable platen 22 and an end plate 23 .
- the movable platen 22 is movable relative to the machine frame 23 via a symbolically represented knuckle joint mechanism 29 .
- Mold halves of a mold 24 can be clamped or fitted (represented dashed) on the fixed platen 21 and the movable platen 22 .
- the fixed platen 21 , the movable platen 22 and the end plate 23 are mounted and guided relative to each other by the rails 25 .
- the mold 24 represented closed in FIG. 17 has at least one cavity.
- FIG. 17 shows a molding machine 2 with an injection unit 18 , wherein the injection unit 18 shown in this embodiment has a plasticizing screw 5 formed as an injection screw, which is also used for plasticizing a material to be plasticized.
- the injection unit 18 of this embodiment has an injection cylinder 4 and a plasticizing screw 5 arranged in the injection cylinder 4 .
- This plasticizing screw 5 is rotatable about an axis of rotation 6 as well as movable axially along the axis of rotation 6 in the conveying direction.
- This drive unit 26 preferably comprises a rotary drive for the rotational movement and a linear drive for the axial injection movement.
- the plasticizing unit 1 (and thus the injection unit 18 ) is in signaling connection with a control or regulating unit 27 .
- Control commands are for example output to the plasticizing unit 1 and/or the drive unit 27 by the control or regulating unit 27 .
- the control or regulating unit 27 can be connected to an operating unit and/or a display device 28 or can be an integral constituent of such an operating unit.
- control or regulating unit 27 of the molding machine 2 at least partly undertakes the function of the control or regulating device 37 of the plasticizing unit 1 , is formed as the latter or alternatively even is implemented independently and/or separately from the latter.
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Abstract
Description
- The present invention relates to a plasticizing unit for a molding machine, a molding machine with such a plasticizing unit, a use of a plasticizing screw, a plasticizing method, as well as a control or regulating device for controlling or regulating a drive of a plasticizing screw of a plasticizing unit.
- ‘Molding machines’ as used herein may include injection-molding machines, transfer-molding machines, presses and the like. Molding machines in which the plasticized material is supplied to an open mold are also entirely conceivable.
- The state of the art is to be outlined below with reference to an injection-molding machine. This applies analogously to molding machines in general.
- Generic plasticizing units for injection-molding machines include an injection cylinder having a dispensing opening, via which dispensing opening a plasticized material can be dispensed, and a plasticizing screw arranged so as to be rotationally and linearly movable in the injection cylinder and has an axis of rotation. A plasticizing zone is formed between the plasticizing screw and the injection cylinder in the radial direction relative to the axis of rotation of the plasticizing screw.
- Corresponding plasticizing units are used in injection-molding machines to plasticize a plasticizable material through a rotational movement of the plasticizing screw. The plasticized material is plasticized due to the shear energy, shear heat, and optionally externally supplied heat energy. This generally takes place in the plasticizing zone of the plasticizing unit.
- After the material to be plasticized has been plasticized, the plasticized material is collected in a space that has formed—the space in front of the screw—wherein the plasticized material can be pushed out of the plasticizing unit through an axial movement of the plasticizing screw and injected into a mold cavity of a mold, where the plasticized material can in turn cure (and can thus solidify, for example, to form a finished product, molded part or semi-finished product).
- It is known from the state of the art to process contaminated plastics as material to be plasticized. These plastics can be for example recyclates, material to be ground or agglomerates, which are used for example in a recycling or compounding application.
- This topic is becoming ever more important, wherein through the recycling of materials to be plasticized (for example thermoplastics) they can be supplied for a new use or a new area of application and thus a marked advantage is created with respect to environmental friendliness.
- However, in order to be able to use such recycled materials in an injection-molding process, it is necessary to purify them, wherein the contaminants are to be removed from the material to be plasticized.
- For this purification or prepurification of the materials to be plasticized, it is known that, in a first step, the contaminated material is plasticized by a continuously operating plasticizing unit and is then purified by degassing processes and filter systems.
- After filtration and degassing, the plasticized material is cooled again and solidifies, wherein the purified material is usually brought directly into a form that is easy to process further, such as for example granules.
- The granules produced from purified and degassed recycled material can then be used subsequently by an injection-molding process in an injection-molding machine.
- However, it has proved to be disadvantageous here that a relatively high expenditure of energy and effort is necessary for the purification of this material and for the preparation of the material for an injection-molding process.
- The object of the present invention is therefore to provide a plasticizing unit and/or a plasticizing method in which the disadvantages of the state of the art are at least in part improved and/or a more energy-efficient recycling of plasticizable material can be implemented and/or a more energy-efficient purification of material to be plasticized is possible and/or a direct processing of material to be purified and plasticized is made possible and/or a more continuous, rapid or energy-saving possibility for plasticizing plasticized material is presented.
- This object is achieved according to the invention by a plasticizing unit for a molding machine as described below, a molding machine with such a plasticizing unit, a use of a plasticizing screw as described below, a plasticizing method as described below, and/or a control or regulating device for controlling or regulating a drive of a plasticizing screw as described below.
- According to the invention, a plasticizing unit for a molding machine includes an injection cylinder having a dispensing opening, via which dispensing opening a plasticized material can be dispensed, and a plasticizing screw arranged so as to be rotationally and linearly movable in the injection cylinder and has an axis of rotation. A plasticizing zone is formed between the plasticizing screw and the injection cylinder in the radial direction relative to the axis of rotation of the plasticizing screw. The plasticizing screw has a dam element, and the injection cylinder has a first opening in the area of the plasticizing zone and/or the dam element, and a has second opening between the dam element and the dispensing opening.
- The present invention thus makes it possible to also use contaminated materials in a process in a molding machine, in particular an injection-molding machine, wherein the contaminated material is plasticized via the plasticizing unit of the molding machine, is guided out of the injection cylinder, can be purified and is then supplied to the injection cylinder again, in order to push out the purified, plasticized material via the plasticizing screw and supply it for example to a mold, more precisely: a mold cavity of a mold.
- This procedure has the substantial advantage over the state of the art that a recycled material has to be plasticized only once and can be purified, which represents a much higher energy efficiency during the processing.
- Furthermore, a simple possibility is created for placing a filter device for the plasticized material outside the injection cylinder, wherein through a molten material line the redirection of the plasticized material, the filter device is virtually freely dimensionable and positionable on the molding machine or the plasticizing unit. The filter device can thereby be precisely adapted to the requirements of the filtering process irrespective of the size of the injection cylinder. Moreover, a cleaning of the filter device or an exchange of filter elements possibly present can be simplified to the effect that the accessibility of the filter device is increased.
- A further advantage is created to the effect that plasticizing units known from the state of the art with plasticizing screws which serve on the one hand for plasticizing and on the other hand for injecting the plasticized material can be utilized, whereby a very compact design of the plasticizing unit can be implemented even in the case of processing of contaminated materials.
- Through the filtering of the plasticized material directly in the molding process, the steps described at the beginning (such as for example the production of granules) can be omitted, which obviously represents a significant improvement in terms of complexity and economic efficiency.
- A corresponding application of an embodiment of the present invention can thus also make a recycling application or compounding application considerably more attractive to a user, wherein the production costs and the production effort are minimized, whereby the environmental friendliness can be increased (through increased use).
- A plasticizing unit according to the invention can have precisely one plasticizing screw or also be formed as a twin-screw design or multi-screw design. In the following description, the plasticizing screw (singular) is sometimes mentioned. However, this is to be understood such that analogous embodiments with several plasticizing screws are likewise applicable.
- Of course, in embodiments with several plasticizing screws several screw axes are present, with respect to which the plasticizing screw is movable in each case axially and in a rotating manner.
- Through its use in already known embodiments of the state of the art, as described for example in the introduction to the description, a device according to the invention or a method according to the invention can be used and subsequently installed.
- By molding machines may be meant injection-molding machines, transfer-molding machines, presses and the like. Molding machines in which the plasticized material is supplied to an open mold are also entirely conceivable.
- Within the meaning of the present document, by a filtration and/or a filtering of a plasticized material may be meant that foreign substances present in the plasticized material are, preferably mechanically, released, removed, discharged and/or separated at least partially from the plasticized material. This can thus also include a separation method.
- Preferably, the dispensing opening of the injection cylinder is connected to at least one injection nozzle and/or a shutoff nozzle and/or is formed as such. For example, the at least one injection nozzle and/or shutoff nozzle can be attached to a mold, in particular an injection mold, and a plasticized material can be supplied to the mold and/or injected into the mold from the injection cylinder via the at least one injection nozzle and/or shutoff nozzle.
- At least one molten material line can be provided, which fluidically connects the first opening to the second opening.
- The at least one molten material line is preferably formed to at least partially supply a plasticized material emerging from the first opening of the injection cylinder to the injection cylinder again via the second opening.
- At least one filter device for filtering plasticized material, in particular plasticized plastic, is or can be arranged in the at least one molten material line.
- Preferably, the at least one molten material line has at least one valve element, preferably a check valve.
- The at least one valve element is arranged in the at least one molten material line between the at least one filter device and the connection of the second opening of the injection cylinder.
- Through a corresponding valve element, it can be ensured that plasticized material, preferably filtered plasticized material, does not change flow direction (for example during the injection process) and flow back into the molten material line again.
- The valve element can be formed as a controllable or regulatable valve element or as a nonreturn valve.
- The valve element can be a two- or three-way valve.
- At least one sensor can be provided in the molten material line, for example in order to detect a signal characteristic of a state and/or a contamination of the plasticized material and/or the filter device.
- A corresponding sensor can be formed as a pressure sensor, temperature sensor, ultrasonic sensor, color sensor, rheometer and/or spectrometer.
- A control or regulating device can take into account a characteristic signal of the at least one sensor in the molten material line for the control or regulation.
- Preferably, the at least one molten material line has at least one discharge opening, preferably between the at least one filter device and the first opening of the injection cylinder.
- Through the provision of a discharge opening, plasticized material can be discharged from the molten material line, in order to be able to flush the plasticized material out of the molten material line for example before shutdown of the process, in order to be able to prevent solidification in the molten material line.
- A further aspect which is made possible through the provision of a discharge opening is the cleaning of the filter device.
- Thus, for example, an outlet opening of the injection cylinder is closed and plasticized material is collected in the space in front of the screw.
- A space in front of the screw can be formed along the axis of rotation of the plasticizing screw between an end of the plasticizing screw facing the dispensing opening and the dispensing opening.
- A pressure is then exerted on this plasticized material collected in the space in front of the screw (the melt cushion) via the plasticizing screw, the dam element and/or the injection plunger. Thus, the plasticized material flows back into the molten material line via the second opening—as the outlet opening is closed—and thus runs through the filter device in the opposite direction, whereby deposits and contaminants are removed from the filter device (i.e. the filter device is backflushed).
- After the filter device has been backflushed, a discharge opening can now be provided between filter device and first opening of the injection cylinder and opened, with the result that the backflushed plasticized material with the contaminants carried therein can be discharged from the filter device.
- Such a corresponding backflushing process can for example be carried out between the production cycles of the plasticizing unit after a given number of cycles or for example in the presence of measurement data which indicate an increased filter blocking.
- A filter blocking or filter coating can, for example, be determined by the measurement of a pressure before the filter device and after the filter device, wherein the pressure difference prevailing between the two measurements represents a meaningful measure thereof.
- Preferably, the at least one filter device has a filter change device, preferably wherein the filter device is formed as a cassette filter.
- A cassette filter can have two or more filter elements, wherein a first filter element in an engaged position is located in a melt stream of the plasticized material, in order to perform a filtration of the plasticized material. In the meantime, a further filter element of the cassette filter is released and is not in contact with the plasticized material.
- While the first filter element is in an engaged position, the further filter element of the cassette filter can be cleaned of contaminants or exchanged.
- If the first filter element has a greater coating and/or contaminants, via the cassette filter the further filter element can be brought into an engaged position via a change device, wherein a filtration of the plasticized material by the further filter element takes place and the first filter element is released for cleaning or changing.
- The filter device can be formed similarly to a cassette deck and have two or more receiving devices for filter elements, wherein, through a change device (preferably an actuator), a receiving device can selectively be brought into an engaged position with the plasticized material and/or a released filter element can be positioned out of or in the receiving device.
- The filter change device can, for example, be formed as a plate screen changer, piston screen changer, cassette screen changer and/or belt filter.
- If a belt filter is provided as filter change device, the belt filter can be guided through the melt stream of the plasticized material continuously or at intervals, wherein blocked filter regions or contaminants of the at least one filter device can be moved out of the melt stream of the material to be plasticized by the filter change device, in order not to impair the ongoing process of the plasticizing unit.
- The moving in and/or out of the at least one filter device can for example take place in an operating state of the plasticizing unit, in which a melt stream of plasticized material is not actively being pushed out by the plasticizing screw, with the result that an active pressure due to a melt stream of the plasticized material does not act on the at least one filter device during the moving in and/or moving out by the filter change device.
- At least one actuator can be provided for conveying the plasticized material against the flow direction of the melt stream, in order to relieve a pressure of the plasticized material applied to the at least one filter device.
- Through a corresponding embodiment, the possibility can be created to influence, utilizing the at least one actuator, pressure conditions prevailing on the at least one filter device (which act on the at least one filter device through the plasticized material) such that a pressure relief of the at least one filter device—which can for example be utilized for a filter change—can be carried out. This is preferably possible without additionally sealing the at least one filter device off from the melt stream of the plasticized material (for example using a check valve).
- Within the meaning of the present document, by a pressure relief may be meant relieving substantial pressures on the at least one filter device. Thus, by a pressure relief may also be meant a relief of the at least one filter device when an approximately equal pressure is exerted on the at least one filter device from both sides.
- In other words, it is characteristic of the pressure relief that forces acting on the at least one filter device—preferably due to the plasticized material (above all in the flow direction of the melt stream)—can be reduced at least far enough to reduce the stresses on the at least one filter device to a sufficient extent that the at least one filter device can be changed (and preferably no damage occurs to the at least one filter device and/or the plasticizing unit when the at least one filter device is being changed).
- Preferably, the at least one actuator is formed by the plasticizing screw and/or by a plunger-cylinder unit, preferably in the form of a melt accumulator.
- The plunger-cylinder unit can be arranged between the at least one filter device and the plasticizing screw in terms of flow or is arranged after the at least one filter device in terms of flow.
- In embodiments wherein the plasticizing screw undertakes a role as at least one actuator, a pressure relief and/or backflushing of the at least one filter device can thus be performed through an axial movement of the plasticizing screw against the flow direction of the plasticized material.
- The dam element can separate the first opening and the second opening from each other in a pushed-forward position, a pulled-back position and/or every operating position lying in between.
- A pushed-forward position of the dam element minus a pulled-back position of the dam element can correspond to a metering stroke of the plasticizing screw.
- Preferably, the plasticizing screw has an injection plunger at the end facing the dispensing opening and/or is coupled to an injection plunger in a movement-locking manner linearly along the axis of rotation.
- The injection plunger can be connected to the plasticizing screw and is formed to execute a relative movement with respect to the plasticizing screw, preferably along an axis of rotation of the plasticizing screw.
- The dam element can be arranged concentrically in the injection cylinder.
- The dam element can be designed as a component that is separate from the plasticizing screw, and can be connected to the plasticizing screw, for example, via a connection, preferably a screw connection. However, it is also entirely conceivable that a part of the plasticizing screw itself is formed as a dam element.
- The dam element can be rotationally decoupled from the injection screw, with the result that a rotational movement of the plasticizing screw (such as occurs, for example, during the plasticizing) is not necessarily transferred to the dam element.
- However, the dam element can also be connected to the plasticizing screw in a movement-locking manner (and thus also rigidly with respect to a rotational movement).
- An injection plunger and/or the dam element can be formed so that it has an outer contour which corresponds to the inner contour of the injection cylinder, wherein between the injection cylinder on the one hand and the injection plunger and/or dam element on the other hand a cross section transverse to an injection direction is formed which is only interrupted by a gap between the injection plunger and/or dam element on the one hand and the injection cylinder on the other hand. This gap is preferably to be designed so small that a plasticized material cannot penetrate through the gap (apart from negligible leakage which does not affect the process or only insignificantly affects it).
- Thus, in a simple manner through the use of an injection plunger and/or a dam element, the plasticizing zone can be separated from the space in front of the screw, whereby the plasticized material is necessarily channeled through the first opening and preferably a molten material line and thus has to pass through a filtration in the molten material line, for example.
- The injection plunger and/or the dam element, with a circumferential surface that is the opposite of the injection cylinder, can be formed leakproof with respect to a plasticized material.
- Within the meaning of the present document, leakproof is to be interpreted such that a leakproofness sufficient for the process cycle can be implemented and operational leakage (for example formed due to wear and tear, tolerances or also damage between injection cylinder and plasticizing screw, dam element or injection plunger) may still be present.
- The first opening from the plasticizing zone and the second opening can be at a distance from each other which corresponds to at least an injection stroke of the plasticizing screw during an injection movement, preferably an injection stroke of the plasticizing screw plus a longitudinal dimension of the dam element along the injection movement.
- The plasticizing screw can have a conveying geometry.
- This conveying geometry can be formed to convey the material to be plasticized and the plasticized material in the direction of the dispensing opening with a given rotational direction and to plasticize it via a shearing and shear heat that forms.
- At least one further conveying geometry can be provided between the dam element and first opening, preferably which further conveying geometry is connected to the plasticizing screw in a movement-locking manner.
- Through the at least one further conveying geometry, the filtered plasticized material which enters the injection cylinder again from the molten material line is plasticized (heated) a further time by shearing and shear heat between the dam element and the dispensing opening and is thus conveyed in the space in front of the screw in the direction of the dispensing opening.
- Through the provision of such a further conveying geometry in the space in front of the screw, the “first-in/first-out” principle can also furthermore be implemented, wherein the filtered plasticized material which is supplied from the molten material line to the injection cylinder in the space in front of the screw can be coordinated to the effect that the plasticized material supplied earlier is also the first to leave the injection cylinder again.
- The first opening and/or the second opening can be formed by at least one recess in the injection cylinder.
- The at least one recess in the injection cylinder can be formed as a longitudinal groove along the axis of rotation, which longitudinal groove preferably has a varying width along the axis of rotation.
- Through a corresponding design, the feeding of the molten material line and thus of the filter device can be controlled or regulated.
- Protection is also sought for the use of a plasticizing screw with a dam element for retaining the plasticized material, in conjunction with a plasticizing unit, preferably a plasticizing unit according to the invention, with an axially movable mounting of the plasticizing screw and preferably an axial drive for the plasticizing screw.
- The plasticizing screw can have a conveying geometry for plasticizing and conveying a material to be plasticized, preferably a plastic.
- Protection is furthermore sought for a plasticizing method, preferably with a plasticizing unit according to the invention, wherein:
-
- a material is plasticized with the aid of a plasticizing screw arranged so as to be rotationally and linearly movable in an injection cylinder,
- material plasticized by the plasticizing screw, preferably a plasticized plastic, is conveyed out of a plasticizing zone present between plasticizing cylinder and plasticizing screw, preferably via a first opening,
- the plasticized material conveyed out of the
plasticizing zone 8 is filtered outside theinjection cylinder 4 and - the filtered plasticized material is returned to the injection cylinder, preferably via at least one second opening.
- The plasticized material can be conveyed out of the injection cylinder into at least one molten material line and is particularly preferably filtered by at least one filter device in the at least one molten material line.
- A space in front of the screw can be formed along the axis of rotation of the plasticizing screw between an end of the plasticizing screw facing the dispensing opening and the dispensing opening.
- Preferably, the filtered plasticized material is pushed out of a space in front of the screw present between the plasticizing screw and a dispensing opening of the injection cylinder via the dispensing opening of the injection cylinder by a dam element coupled to the plasticizing screw in a movement-locking manner or attached to the plasticizing screw via a linear movement of the plasticizing screw.
- A pressure can be exerted on the filtered plasticized material by a linear movement of the injection screw, whereby the filtered plasticized material is conveyed back into at least one molten material line arranged at the second opening, preferably whereby at least one filter device arranged in the at least one molten material line is backflushed.
- Protection is furthermore sought for a control or regulating device for controlling or regulating a drive of a plasticizing screw of an embodiment according to the invention of a plasticizing unit, which control or regulating device is formed to carry out a method according to the invention.
- The control or regulating device can be formed for controlling or regulating a filter device, a filter change device, a valve element, a discharge opening, a plasticizing screw. It can alternatively or additionally be provided that the control or regulating device is formed to control or regulate a drive device, a drive and/or a control or regulating element of one of the previously listed elements.
- The control or regulating device is or can be connected in a signal-carrying manner to at least one sensor, wherein preferably a characteristic signal of the at least one sensor is taken into account for the control or regulation.
- By a control or regulating device may be meant those components of a plasticizing unit which allow a control of actuators, drives and/or drive control systems, which in particular comprises so-called “programmable logic controllers” (PLCs). This can also include receiving sensor data and carrying out calculation processes for a control process, which can be carried out in real time depending on the control diagram.
- The control or regulating unit can be realized by a central machine control system or a control or regulating unit of the molding machine or undertakes the tasks thereof.
- The function of the control or regulating device can be undertaken by a control or regulating device linked directly to the molding machine and/or the plasticizing unit or a control or regulating device connected to the molding machine and/or the plasticizing unit by a data transmission connection.
- The data transmission connection can preferably be formed as a remote data transmission connection. The remote data transmission connection can be realized by means of a LAN (Local Area Network), WLAN (Wireless Local Area Network), WAN (Wide Area Network) and/or different (internet) protocols.
- The data transmission and relaying to the manufacturer or a maintenance service provider, as well as the processing by them, can likewise be provided.
- The at least one control or regulating device can be formed to control or regulate the plasticizing screw and/or a drive of the plasticizing screw taking into account characteristic signals of at least one sensor, preferably at least one sensor in the molten material line, so that a filter device in the molten material line between the first opening and the second opening is backflushed.
- This can be effected in that a filter blocking or filter coating is ascertained by a control or regulating device via the at least one sensor and the characteristic signal measured by the at least one sensor.
- Such a sensor can be, for example, at least one or a combination of the following:
-
- a pressure sensor, which measures a pressure increase before the filter device,
- at least two pressure sensors, which measure a pressure drop in the flow direction along the filter device, in particular before and after the filter device,
- a color or optical sensor, which measures a blocking and/or coating of the filter device by detecting a visual contamination of the filter device and/or the plasticized material and/or
- a sensor of other process parameters which allow a blocking and/or coating of the filter device to be deduced.
- With the aid of predefined stored or predefinable limit values and/or limit ranges, the control or regulating device can be formed to perform and/or signal a necessary filter change and/or a filter cleaning of the filter device because of the determined filter blocking or filter coating.
- A corresponding filter change and/or a filter cleaning can for example be signaled, by the control or regulating device through acoustic, haptic and/or optical signals, to a user who can initiate a filter change and/or a filter cleaning. It can also be provided that, in the case of too great a filter blocking or filter coating, the control or regulating device is formed to automatically interrupt the plasticizing process, in order to carry out a filter change and/or a filter cleaning.
- A signal characteristic of the determined filter blocking or the filter coating can be transmitted by the control or regulating device to a manufacturer or a maintenance service provider, who, on the basis of the transmitted signals, can provide, for example in an automated manner, maintenance personnel and/or maintenance material (such as for example filter elements for the filter device) for the filter change and/or for the filter cleaning.
- When a filter change is carried out, the control or regulating device can be formed:
-
- to interrupt a plasticizing process,
- to carry out a pressure relief of the at least one filter device,
- to carry out a filter change, for example by controlling or regulating a filter change device, and
- to resume a plasticizing process.
- When a filter cleaning is carried out, the control or regulating device can be formed:
-
- to interrupt a plasticizing process,
- to carry out a backflushing of the filter device, for example by controlling or regulating a plasticizing screw,
- to discharge a backflushed plasticized material from the plasticizing unit, for example by controlling or regulating a discharge opening, and
- to resume a plasticizing process.
- Further advantages and details of the invention are revealed by the figures and the associated description of the figures. There are shown in:
-
FIGS. 1 and 2 show a first embodiment of a plasticizing unit according to the invention, -
FIGS. 3 and 4 show a second embodiment of a plasticizing unit according to the invention, -
FIG. 5 shows a third embodiment of a plasticizing unit according to the invention, -
FIG. 6 shows a fourth embodiment of a plasticizing unit according to the invention, -
FIG. 7 shows a fifth embodiment of a plasticizing unit according to the invention, -
FIG. 8 shows a sixth embodiment of a plasticizing unit according to the invention, -
FIGS. 9 and 10 show a seventh embodiment of a plasticizing unit according to the invention, -
FIGS. 11 and 12 show an eighth embodiment of a plasticizing unit according to the invention, -
FIGS. 13 and 14 show a ninth embodiment of a plasticizing unit according to the invention, -
FIG. 15 shows a tenth embodiment of a plasticizing unit according to the invention, -
FIGS. 16 a-16 c show a filter device with filter change device, and -
FIG. 17 shows a molding machine. -
FIG. 1 shows a first embodiment of aplasticizing unit 1, comprising aninjection cylinder 4 and aplasticizing screw 5 arranged in theinjection cylinder 4. - The
plasticizing screw 5 is formed to perform, in theinjection cylinder 4, a rotational movement about the axis ofrotation 6 for plasticizing a material, as well as to perform a linear movement along the axis ofrotation 6 for pushing out the plasticized material. - The
injection cylinder 4 has adispensing opening 3, via which dispensingopening 3 plasticized material can be pushed out of the injection cylinder and can for example be injected into amold 24. - A space in front of the
screw 7 is provided along the axis ofrotation 6 of theplasticizing screw 5 between the dispensingopening 3 and the end of theplasticizing screw 5 facing the dispensingopening 3. - The
plasticizing zone 8 is formed between theplasticizing screw 5 and theinjection cylinder 4 in the radial direction relative to the axis ofrotation 6 of theplasticizing screw 5. - A
molten material line 9 is furthermore provided, which branches off from theinjection cylinder 4 out of theplasticizing zone 8 via thefirst opening 12 of theinjection cylinder 4 and opens into theinjection cylinder 4 again via thesecond opening 13 of theinjection cylinder 4 with the space in front of thescrew 7. - The plasticizing screw furthermore has a
dam element 11 at an end facing the dispensingopening 3, wherein in this embodiment thedam element 11 is formed in one piece with theplasticizing screw 5. - The
filter device 10 for filtering a plasticized material is furthermore provided in thebypass line 9. - The
molten material line 9 can be sealed off with respect to the space in front of thescrew 7 by means of thevalve element 16—to be precise: a check valve. - During a cycle of the plasticizing unit, a material to be plasticized is now moved from a rear area of the
plasticizing screw 5 via the conveyinggeometry 15 of theplasticizing screw 5 in the direction of theplasticizing zone 8, wherein due to the shearing, shear heat and optionally externally introduced heat the material to be plasticized is plasticized in theplasticizing zone 8. - The material and the plasticized material are conveyed by the conveying
geometry 15 of theplasticizing screw 5 in the direction of the dispensingopening 3 until the plasticized material emerges from theplasticizing zone 8 via thefirst opening 12 from theinjection cylinder 4 and is channeled into themolten material line 9. - This emerging of the plasticized material from the
plasticizing zone 8 and theinjection cylinder 4 is facilitated by thedam element 11—more precisely: the side of thedam element 11 facing away from the space in front of thescrew 7. - The
dam element 11 has an external geometry that corresponds to the internal geometry of theinjection cylinder 4, with the result that betweendam element 11 andinjection cylinder 4 only a small gap remains, which is chosen so that it is formed leakproof with respect to a plasticized material. - This means that the gap between
dam element 11 andinjection cylinder 4 is formed so small that plasticized material cannot penetrate through it. - The material plasticized by the
plasticizing screw 5 is thus driven through themolten material line 9 and thefilter device 10 arranged therein. - The
filter device 10 is formed to filter contaminants out of the plasticized material, wherein these contaminants remain in the filter device and the filtered plasticized material is channeled through themolten material line 9 via thevalve element 16 and thesecond opening 13 of theinjection cylinder 4 back into theinjection cylinder 4—to be precise: into the space in front of thescrew 7. - The filtered plasticized material now accumulates in the space in front of the
screw 7. - As the
dispensing opening 3 is closed during the plasticizing (for example via a hotrunner closure system), a melt cushion consisting of plasticized material builds up in the space in front of thescrew 7, which pushes theplasticizing screw 5 away backwards, whereby the space in front of thescrew 7 increases in size. - This plasticizing process (often also referred to as metering) is performed until a desired quantity of plasticized material is present in the space in front of the screw 7 (as can be seen in
FIG. 2 ). - If this desired plasticized material for the further processing is achieved in the space in front of the
screw 7, thevalve element 16 is closed, the dispensingopening 3 is opened and then thedam element 11 is moved in the direction of the dispensingopening 3 via a linear movement of theplasticizing screw 5, wherein, via thedam element 11, the plasticized material is pushed out of the space in front of thescrew 7 via thedispensing opening 3 and is for example supplied to amold 24—to be precise: a cavity of themold 24. -
FIGS. 3 and 4 show a further embodiment of aplasticizing unit 1, wherein the plasticizing unit is again represented during a plasticizing inFIG. 3 , andFIG. 4 shows theplasticizing unit 1 just before the injection process. - In comparison with
FIGS. 1 and 2 , the embodiment of theplasticizing unit 1 ofFIGS. 3 and 4 has aplasticizing screw 5 which is again formed in one piece with adam element 11, but wherein betweendam element 11 and dispensing opening 3 a further conveyinggeometry 14 is provided, which is formed by a screw extension. - After the filtration of the plasticized material by the
filter device 10, the plasticized material returned to the space in front of thescrew 7 via thesecond opening 13 can be conveyed, via this further conveyinggeometry 14, further in the direction of the dispensingopening 3 and heated/plasticized once again via shearing and shear heat. - A
nonreturn valve 30, which serves to prevent the plasticized material from flowing back out of the space in front of thescrew 7 to thefurther screw geometry 14 during the injection, is arranged at the end of the further conveyinggeometry 14 facing the dispensingopening 3. - Through the provision of the
nonreturn valve 30 and thefurther screw geometry 14, avalve element 16 is not necessary in the embodiment ofFIGS. 3 and 4 . - It can also be provided that the
plasticizing screw 5, as represented inFIGS. 4 and 5 , only has a cylindrical extension instead of thefurther screw geometry 14, wherein anonreturn valve 30 can be arranged at an end of the cylindrical extension facing the dispensing opening, wherein avalve element 16 can likewise be dispensed with by means of such an embodiment. -
FIG. 5 shows a third embodiment of aplasticizing unit 1 which, in comparison with the embodiment ofFIG. 1 , has a converse conveyinggeometry 35 on theplasticizing screw 5. - This converse conveying
geometry 35 is formed in an area between thefirst opening 12 and thesecond opening 13 of theinjection cylinder 4, more precisely in an area between thefirst opening 13 and thedam element 11. - The converse conveying
geometry 35 of theplasticizing screw 5 changes from the conveyinggeometry 15 of theplasticizing screw 5 into the converse conveyinggeometry 35. - Through the provision of the converse conveying
geometry 35, the plasticized material can additionally be retained in the area of the transition from the conveyinggeometry 15 into the converse conveyinggeometry 35 and an emerging of the plasticized material from theinjection cylinder 4 through thefirst opening 12 can be promoted. -
FIG. 6 shows a fourth embodiment of aplasticizing unit 1 which, in comparison with the embodiment ofFIG. 1 , has adummy 36 instead of thefilter device 10. - Such a
dummy 36 or also placeholder can for example be inserted into themolten material line 9 for delivery and/or transport of theplasticizing unit 1, in order to prevent damage. - When the plasticizing unit is put into operation, this
dummy 36 can be removed from themolten material line 9 and replaced with afilter device 10 for the filtration of the plasticized material. - However, it can also be provided that the
dummy 36 and/or thefilter device 10 are replaced with a connecting pipe or a continuousmolten material line 9, wherein a clean material to be plasticized, which requires no further filtration (as can be seen in the fifth embodiment ofFIG. 7 ), can for example be processed. - Through the provision of a connecting pipe or a continuous
molten material line 9, the processing of an already clean plasticized material can thus be optimized in that, for example, an unnecessary flow obstruction, as represented by afilter device 10, can be avoided. -
FIG. 8 shows a sixth embodiment of aplasticizing unit 1, which has a control or regulating device 37. - This control or regulating device 37 of the
plasticizing unit 1 is connected by signal-carrying connections (represented dashed here) to adrive unit 26 of theplasticizing screw 5, afilter change device 17 of thefilter device 10, thevalve element 16 and ashutoff nozzle 38 of the dispensingopening 3, wherein the control or regulating device 37, with the aid of the signal-carrying connections, is formed to control or regulate these elements and optionally receive characteristic signals from sensors which are arranged on these elements. - Thus, the control or regulating unit 37 can be formed, for example for the measurement of a coating or blocking of the
filter device 10, to measure a pressure before and after thefilter device 10 with the aid of correspondingly arranged pressure sensors and via the pressure difference between these two pressures—when the pressure difference becomes too great—to indirectly refer to the coating or blocking of thefilter device 10. - When this coating or blocking of the
filter device 10 reaches or exceeds a stored or predefinable limit value, the control or regulating unit 37 can be formed to carry out a filter change and/or a filter cleaning. - A filter change can be performed by the control or regulating unit 37 through a corresponding control or regulation of actuators of the
plasticizing screw 5 and thefilter change device 17. Reference may be made at this point to the followingFIGS. 16 a to 16 c , wherein a filter change will be expanded on. - In the case of a filter cleaning by the control or regulating unit 37, a backflushing can for example be performed, wherein a cleaning of the filter device by backflushing the plasticized material through the
filter device 10 can be performed by the control or regulating device 37 (as already described previously) through a corresponding control or regulation of theplasticizing screw 5, thevalve element 16, ashutoff nozzle 38 of the dispensingopening 3 and optionally an actuator orvalve element 16 of a discharge opening. -
FIGS. 9 and 10 show a further embodiment of aplasticizing unit 1, wherein theplasticizing screw 5 has aninjection plunger 39. - Through the provision of a
plasticizing screw 5 with aninjection plunger 39, the possibility can be created that a conveyinggeometry 15 of theplasticizing screw 5 is kept axially fixed during the entire plasticizing process, wherein, through the prevention of axial movements of thedam geometry 11, a better sealing of thedam geometry 11 with respect to the inner wall of theinjection cylinder 4 as well as lower wear betweendam geometry 11 andinjection cylinder 4 are implemented. - During a cycle of the
plasticizing unit 1, a material to be plasticized is now moved from a rear area of theplasticizing screw 5 via the conveyinggeometry 15 of theplasticizing screw 5 in the direction of theplasticizing zone 8, wherein due to the shearing, shear heat and optionally externally introduced heat the material to be plasticized is plasticized in theplasticizing zone 8. - The material and the plasticized material are conveyed by the conveying
geometry 15 of theplasticizing screw 5 in the direction of the dispensingopening 3 until the plasticized material emerges from theplasticizing zone 8 via thefirst opening 12 from theinjection cylinder 4 and is channeled into themolten material line 9. - This emerging of the plasticized material from the
plasticizing zone 8 and theinjection cylinder 4 is facilitated by thedam element 11. - The material plasticized by the
plasticizing screw 5 is thus driven through themolten material line 9 and thefilter device 10 arranged therein. - The
filter device 10 is formed to filter contaminants out of the plasticized material, wherein these contaminants remain in the filter device and the filtered plasticized material is channeled through themolten material line 9 via thevalve element 16 and thesecond opening 13 of theinjection cylinder 4 back into theinjection cylinder 4—to be precise: into the space in front of thescrew 7. - The filtered plasticized material now accumulates in the space in front of the
screw 7. - As the
dispensing opening 3 is closed during the plasticizing (for example via a hotrunner closure system), a melt cushion consisting of plasticized material builds up in the space in front of thescrew 7, which pushes theinjection plunger 39 away backwards, whereby the space in front of thescrew 7 increases in size. - This plasticizing process (often also referred to as metering) is performed until a desired quantity of plasticized material is present in the space in front of the screw 7 (as can be seen in
FIG. 9 ). - If this desired plasticized material for the further processing is achieved in the space in front of the
screw 7, thevalve element 16 is closed, the dispensingopening 3 is opened and thendam element 11 is moved in the direction of the dispensingopening 3 via a linear movement of theinjection plunger 39 of theplasticizing screw 5, wherein, via theinjection plunger 39, the plasticized material is pushed out of the space in front of thescrew 7 via thedispensing opening 3 and is for example supplied to amold 24—to be precise: a cavity of the mold 24 (as can be seen inFIG. 10 ). - The remaining features of
FIGS. 9 and 10 substantially correspond to those ofFIGS. 1 and 2 . -
FIG. 11 andFIG. 12 show an embodiment which, in comparison with the embodiment ofFIG. 5 andFIG. 6 , has a nonreturn valve instead of avalve element 16 formed as a 2-way valve. -
FIG. 13 andFIG. 14 show an embodiment which, in comparison with the embodiment ofFIG. 3 andFIG. 4 , has a converse conveyinggeometry 35 on theplasticizing screw 5. - This converse conveying
geometry 35 is formed in an area between thefirst opening 12 and thesecond opening 13 of theinjection cylinder 4, more precisely in an area between thefirst opening 13 and thedam element 11. - The converse conveying
geometry 35 of theplasticizing screw 5 changes from the conveyinggeometry 15 of theplasticizing screw 5 into the converse conveyinggeometry 35. - Through the provision of the converse conveying
geometry 35, the plasticized material can additionally be retained in the area of the transition from the conveyinggeometry 15 into the converse conveyinggeometry 35 and an emerging of the plasticized material from theinjection cylinder 4 through thefirst opening 12 can be promoted. - It can for example be provided that the
first opening 12 is formed as a recess in theinjection cylinder 4, which recess is formed by a longitudinal groove with a varying width along the axis ofrotation 6, as can be seen in the embodiment ofFIG. 15 . -
FIG. 15 shows a top view of aninjection cylinder 4, wherein the inside of theinjection cylinder 4 and thus theplasticizing screw 5 arranged in theinjection cylinder 4 can be recognized through thefirst opening 12. - A flow direction of the plasticized material is illustrated by the arrow represented, wherein the material plasticized by the
plasticizing screw 5 is conveyed in the direction of thefirst opening 12, before the plasticized material leaves theinjection cylinder 4 via thefirst opening 12. - If the dam element (such as for example in the case of an embodiment of
FIGS. 1-8 or 13-14 ), together with theplasticizing screw 5, now makes an axial movement in theinjection cylinder 4, it may be the case that, in certain operating states, areas of thefirst opening 12 are at least partially covered (see in particularFIG. 2 ). - In order nevertheless to be able to implement a sufficient volume flow of plasticized material out of the
injection cylinder 4, it can be provided to implement thefirst opening 12 with a varying width along the axis ofrotation 6 of theplasticizing screw 5. - Through a corresponding design, the feeding of the
molten material line 9 and thus of thefilter device 10 can be controlled or regulated, depending on what proportion of thefirst opening 12 is cleared by thedam element 11. - Due to the varying width of the
first opening 12, it can be achieved that for example a relatively large melt stream gets through thefirst opening 12, even if a relatively small part of thefirst opening 12 is cleared by the dam element. - Moreover, it can for example be achieved that the melt stream can be relatively finely regulated in the area of the maximum melt stream (if the
first opening 12 is completely or almost completely cleared) in that thefirst opening 12 at the end that is on the left inFIG. 15 is relatively narrow. -
FIGS. 16 a to 16 c show, purely schematically, afilter device 10 which has afilter change device 17. - This
filter change device 17 has afirst filter element 33 and a (further)second filter element 34, which can be alternately added to afluid stream 31 consisting of plasticized material in order to filter the plasticized material and/or to remove contaminants from it. - Correspondingly (see
FIG. 16 a ), first of all afirst filter element 33 is located in themolten material line 9 in order to filter thefluid stream 31 of plasticized material. - If the
first filter element 33 now has too great a coating (contamination), a filter change can be carried out. - For the measurement of a coating, a pressure can for example be measured before and after the
filter element filter element - The cyclic filter change represents an alternative solution, wherein, according to empirical values, the
filter elements - During a filter change (such as is represented by
FIG. 16 b ), thefluid stream 31 of plasticized material is briefly interrupted and, via achange system 32, thefirst filter element 33 is taken out of themolten material line 9 and replaced with thesecond filter element 34. - After the change has been effected, the
fluid stream 31 of plasticized material can be started again and supplied to the second filter element 34 (seeFIG. 16 c ). - The
filter element 33 can then be cleaned while thesecond filter element 34 is being used and exchanged again once a coating of thesecond filter element 34 in thefluid stream 31 of plasticized material becomes too great. - It can be provided that the
molten material line 9 is formed as a hotrunner system, with the result that during the filter change the plasticized material in themolten material line 9 does not cool too much and possibly solidify. - The
molding machine 2 represented by way of example inFIG. 17 is an injection-molding machine and has aninjection unit 18 and a clamping unit 19, which are arranged together on amachine frame 20. Themachine frame 20 could alternatively also be formed multi-part. - The clamping unit 19 has a fixed
platen 21, amovable platen 22 and anend plate 23. - The
movable platen 22 is movable relative to themachine frame 23 via a symbolically represented knucklejoint mechanism 29. - Mold halves of a
mold 24 can be clamped or fitted (represented dashed) on the fixedplaten 21 and themovable platen 22. - The fixed
platen 21, themovable platen 22 and theend plate 23 are mounted and guided relative to each other by therails 25. - The
mold 24 represented closed inFIG. 17 has at least one cavity. An injection channel, via which a plasticized material can be supplied to theplasticizing unit 2, leads to the cavity. -
FIG. 17 shows amolding machine 2 with aninjection unit 18, wherein theinjection unit 18 shown in this embodiment has aplasticizing screw 5 formed as an injection screw, which is also used for plasticizing a material to be plasticized. - The
injection unit 18 of this embodiment has aninjection cylinder 4 and aplasticizing screw 5 arranged in theinjection cylinder 4. Thisplasticizing screw 5 is rotatable about an axis ofrotation 6 as well as movable axially along the axis ofrotation 6 in the conveying direction. - These movements are driven via a schematically represented
drive unit 26. Thisdrive unit 26 preferably comprises a rotary drive for the rotational movement and a linear drive for the axial injection movement. - The plasticizing unit 1 (and thus the injection unit 18) is in signaling connection with a control or regulating
unit 27. Control commands are for example output to theplasticizing unit 1 and/or thedrive unit 27 by the control or regulatingunit 27. - The control or regulating
unit 27 can be connected to an operating unit and/or adisplay device 28 or can be an integral constituent of such an operating unit. - It can be provided that the control or regulating
unit 27 of themolding machine 2 at least partly undertakes the function of the control or regulating device 37 of theplasticizing unit 1, is formed as the latter or alternatively even is implemented independently and/or separately from the latter. -
-
- 1 plasticizing unit
- 2 molding machine
- 3 dispensing opening
- 4 injection cylinder
- 5 plasticizing screw
- 6 axis of rotation
- 7 space in front of the screw
- 8 plasticizing zone
- 9 molten material line
- 10 filter device
- 11 dam geometry
- 12 first opening of the injection cylinder
- 13 second opening of the injection cylinder
- 14 further conveying geometry
- 15 conveying geometry
- 16 valve element
- 17 filter change device
- 18 injection unit
- 19 clamping unit
- 20 machine frame
- 21 fixed platen
- 22 movable platen
- 23 end plate
- 24 mold
- 25 rail
- 26 drive unit
- 27 control or regulating unit
- 28 display device
- 29 knuckle joint mechanism
- 30 nonreturn valve
- 31 fluid stream
- 32 change system
- 33 first filter element
- 34 second filter element
- 35 converse conveying geometry
- 36 dummy
- 37 control or regulating device
- 38 shutoff nozzle
- 39 injection plunger
Claims (20)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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ATA50509/2022A AT525668B1 (en) | 2022-07-11 | 2022-07-11 | Plasticizing unit for a molding machine |
ATA50509/2022 | 2022-07-11 |
Publications (1)
Publication Number | Publication Date |
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US20240009889A1 true US20240009889A1 (en) | 2024-01-11 |
Family
ID=86721591
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US18/215,557 Pending US20240009889A1 (en) | 2022-07-11 | 2023-06-28 | Plasticizing unit for a molding machine |
Country Status (4)
Country | Link |
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US (1) | US20240009889A1 (en) |
CN (1) | CN117382124A (en) |
AT (1) | AT525668B1 (en) |
DE (1) | DE102023118020A1 (en) |
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AT407505B (en) * | 1999-07-12 | 2001-04-25 | Bacher Helmut | DEVICE AND METHOD FOR INTAKING SENSITIVE ADDITIVES IN THERMOPLASTIC PLASTIC MATERIAL |
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2022
- 2022-07-11 AT ATA50509/2022A patent/AT525668B1/en active
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2023
- 2023-06-28 US US18/215,557 patent/US20240009889A1/en active Pending
- 2023-07-07 DE DE102023118020.7A patent/DE102023118020A1/en active Pending
- 2023-07-10 CN CN202310835487.4A patent/CN117382124A/en active Pending
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US4730935A (en) * | 1986-05-09 | 1988-03-15 | Hermann Berstorff Maschinenbau Gmbh | Extrusion apparatus for the production of mixtures of molten synthetic material |
US4897236A (en) * | 1987-09-02 | 1990-01-30 | Hermann Berstorff Maschinenbau Gmbh | Method and apparatus for the continuous manufacture of rubber or polymer-based mixtures containing additives |
US4959186A (en) * | 1988-05-27 | 1990-09-25 | Rhodia Ag | Extrusion process and single-, dual- or multiple-screw extruder |
US5130070A (en) * | 1990-06-01 | 1992-07-14 | Hermann Berstorff Maschinenbau Gmbh | Method of reverse degassing an extrusion melt and an extrusion device therefor |
US5419634A (en) * | 1991-08-29 | 1995-05-30 | Bacher; Helmut | Apparatus for filtering and extruding synthetic plastic scrap material |
US5651944A (en) * | 1993-06-08 | 1997-07-29 | Schulz; Helmuth | Apparatus for degassing thermoplastic synthetic plastics material |
US6196820B1 (en) * | 1998-03-11 | 2001-03-06 | Mannesmann Ag | Device for filtering plastics in injection molding machines |
US6206558B1 (en) * | 1998-03-27 | 2001-03-27 | Sencorp Systems, Inc. | Extrusion system |
US20040151058A1 (en) * | 2001-05-30 | 2004-08-05 | Bernhard Schafer | Method and device for regulating pressure in a single-screw degassing extruder or in a cascade extruder |
US20100034917A1 (en) * | 2006-04-27 | 2010-02-11 | Erema Engineering Recycling Maschinen Und Anlagen Gesellschaft M.B.H. | Device For Degassing And Filtering Plastic Melts |
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Also Published As
Publication number | Publication date |
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CN117382124A (en) | 2024-01-12 |
AT525668A4 (en) | 2023-06-15 |
DE102023118020A1 (en) | 2024-01-11 |
AT525668B1 (en) | 2023-06-15 |
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